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Services -> Ticks

The District offers the following services with respect to ticks:

  • Disease Surveillance
  • Tick identification
  • Public Education

Tick Identification:

The District has an ongoing tick-borne disease surveillance program with an emphasis on Lyme Disease.

Engorged Female (EF),
and Male (M) ticks

If you have found a tick on yourself or your pet and want to have it identified, please follow the directions below:

  • The specimen must be alive (put the tick in a plastic bag or container with a piece of moist paper towel to provide humidity).
  • Write down the address where the tick was acquired.
  • Note how long the tick may have been attached.

Information about ticks:

Tick Biology

There are 49 species of ticks in California, most of which never come in contact with people because they live in the nests of birds, bats, or wild mammals. Ticks are divided into 2 groups "hard ticks" (Ixodid ticks) and "soft ticks" (Argasids). Soft ticks are not familiar to most people in the Bay Area. Most are parasites of birds and live in their nests. A few species live in the burrows of squirrels or rabbits.

The typical tick encountered by humans and their pets in San Mateo County is an example of a hard tick. These ticks have a three stage life cycle: larva, nymph and adult. All three stages feed on blood and a blood meal is required to molt to the next stage or lay eggs. Hard ticks attach to their hosts for long periods of time (3-7days, depending on the life stage) swelling to many times their unfed size. After completing the blood meal, they drop off, digest the blood, and molt to the next stage or lay eggs. Each stage attaches to a separate host. Completion of the entire life cycle can take many months or even a couple of years. The different life stages of a tick often feed on different kinds of hosts. For example, larvae and nymphs of the Pacific Coast tick (Dermacentor occidentalis) feed on mice and other rodents. The adult stage of this tick feeds on deer or other large animals.

There are 28 species of hard ticks in California. Twenty-one of these have either been recorded in San Mateo County or could occur here. Of these 21 species, only three are likely to be encountered by people or their pets. The remaining 18 species feed on specific groups of animals (ie. birds, bats, rodents, rabbits, etc.) and are closely associated with the nests, burrows or bedding areas of these animals. These ticks are almost never encountered by humans and can only be found by examining wild animals or their nests.

For more information about the three ticks you might encounter along the trail - Click Here

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What diseases do ticks transmit?

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Common ticks of San Mateo County

Although there are 21 species of hard ticks in San Mateo County, the list below are the most common ticks that people and pets contact in the environment.

Ticks: Characteristics:
Ixodes pacificus
Western Black-legged Tick"
  • Adults quest along trails November to May
  • Adults feed readily on humans, horses, dogs and other large mammals
  • Larvae and nymphs are active March to early August, peaking in April to June
  • Larvae and nymphs feed primarily on lizards but may also attach to rodents and people
  • Importance: Primary vector of Lyme disease to humans in California
Dermacentor occidentalis
"Pacific Coast Tick"

  • Adults feed on cattle, horses, deer, dogs and humans
  • Adults reach peak activity from April through May but are present along trails from November through August
  • Larvae and nymphs feed on small rodents and other small mammals in spring and summer
  • Vector of Tularemia and Rocky Mountain Spotted Fever, and both have been detected in ticks in San Mateo County
Dermacentor variablis
"American Dog Tick"

  • Adults feed on dogs and large mammals, including humans
  • Adults along trails primarily from March through July
  • Larvae and nymphs feed on rodents and other small mammals, they are active from late winter to summer
  • Vector of Tularemia and Rocky Mountain Spotted Fever, and both have been detected in this tick in San Mateo County

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